Along with rapid popularization of mobile networks on a global scale, in particular rapid growth of 3-Generation (3G) networks, each operator attracts users in manners of communication fee subsidy or mobile terminal bundling in terms of selling modes of mobile terminals such as mobile phones, tablets and data cards to increase and consolidate the number of users. In order to prevent user loss and reward early subsidy investment of operators, the operators usually protect own customer resources and expect their own customers to use their own specified network resources only by network locking. In a prior art, a network locking on a mobile terminal is implemented by limiting the mobile terminal to use only a specified data card such as a Subscriber Identity Module (SIM) card. An existing network locking solution mainly includes the following steps:
Step 1, when producing a terminal, a mobile terminal manufacturer writes a legal Public Land Mobile Network (PLMN) number segment, a locking identifier and an unlocking code value into a flash of the terminal;
Step 2, when a terminal user inserts a card into the terminal, the terminal reads a PLMN number segment from the SIM card or acquires the PLMN number segment from a network where the SIM card gets successfully registered, and then compares the read or acquired PLMN number segment with the preset PLMN number segment of the terminal, all functions of the terminal are enabled if they are consistent, and if they are inconsistent, all the functions of the terminal are disabled; and
Step 3, when the terminal user sends an unlocking code to the terminal, the terminal compares the sent unlocking code with a preset unlocking code of the terminal by virtue of a certain algorithm and the like, clears a network locking identifier if they are consistent, and determines that unlocking fails if they are inconsistent.
In the existing network locking solution, the unlocking code value is directly obtained merely according to a set network locking parameter, and is easy to be tampered and cracked illegally, which may make the terminal easy to be unlocked illegally and lower security of network locking of the terminal.